transvaginal?

has anyone else heard that transvaginal u/s could br harmful? Maybe weakin the cervix or introduce bacteria into the cervix? 
 i have heard u/s in general bc if the radiation could possible be not great for baby or mother. 
i had a m/c a few days after a transvaginal a few months ago and im pregnant again and considering not letting them go "up in there" again.
​Sound reasonable or insane?